As a device to cool a heating component such as a Central Processing Unit (CPU) mounted on an electronic device, a heat pipe is known. The heat pipe is a device that transports heat using phase change of working fluid.
As an example of a heat pipe, a loop heat pipe includes an evaporator that vaporizes working fluid by heat of a heating component and a condenser that condenses the vaporized working fluid in which the evaporator and the condenser are connected by a liquid line and a vapor line that form a loop flow path. In the loop heat pipe, the working fluid flows in the loop flow path in one direction.
Further, a porous body is provided in the liquid line of the loop heat pipe so that the working fluid in the liquid line is induced to flow toward the evaporator by capillary force generated in the porous body and vapor is prevented from reversely flowing from the evaporator to the liquid line. A plurality of pores are formed in the porous body. Each of the pores is formed by stacking a plurality of metal layers in each of which through holes are formed such that the through holes of different metal layers partially overlap (see Patent Document 1, for example).
In the above described loop heat pipe, water heated at the evaporator becomes vapor and moves in the vapor line. However, a part of the vapor becomes a water drop by dew condensation while moving further from a heat source.
Such a condensed water drop cannot transfer heat. Further, there is a problem that, if such a condensed water drop exists in the vapor line, condensation of the vapor is promoted by contacting the water drop, in addition to lowering movement of the vapor. Further, if condensed water drops remain in the condenser, condensation of the vaporized working fluid is suppressed.